JP2005129656A - Surface-mounting electronic circuit unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-mounting electronic circuit unit which does not include a fault by soldering at the time of surface mounting and ensures higher surface mounting process. <P>SOLUTION: The surface-mounting electronic circuit unit shields with an insulating film 8 between the immediately adjacent solder 7 and land 3 because the insulating film 8 is provided over the lower surface of the solder 7 and the lower surface 1b of the circuit board 1 located near the lower surface of the solder 7. Accordingly, when the circuit board 1 is surface-mounted to a mother board, the solder 7 and the land 3 does not become conductive with the solder 7 at the time of surface mounting, and a fault of solder 7 can be eliminated at the time of surface mounting, resulting in reliable soldering process. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a surface mount electronic circuit unit suitable for use in a voltage controlled oscillator or the like.

  FIG. 10 is a perspective view of a conventional surface-mount electronic circuit unit, FIG. 11 is a bottom view of the conventional surface-mount electronic circuit unit, and FIG. 12 is a conventional surface. It is principal part sectional drawing of a mounting type electronic circuit unit.

  Next, the configuration of a conventional surface mount electronic circuit unit will be described with reference to FIGS. 10 to 12. A wiring pattern 52 is formed on the upper surface 51 a of the circuit board 51 and the lower surface 51 b of the circuit board 51. A plurality of land portions 53 are provided.

  Further, the end surface 51c of the circuit board 51 is provided with a notch portion 51d penetrating in the vertical direction, and a conductor 54 is provided on the wall surface of the notch portion 51d. A variety of electronic components 55 are mounted to form a desired electric circuit.

  The metal box-shaped cover 56 is disposed so as to cover the electronic component 55, and with the mounting leg 56a inserted into the cutout portion 51d, the metal box-shaped cover 56 is soldered 57 to the conductor 54, and the conventional surface. A mounting electronic circuit unit is configured. (For example, see Patent Document 1)

  As shown in FIGS. 11 and 12, the conventional surface-mount type electronic circuit unit having such a configuration includes a solder 57 for mounting the mounting leg 56a and a lower end of the conductor 54 on the lower surface 51b of the circuit board 51. Is exposed from.

  The solder 57 and the conductor 54 are disposed between the signal (hot-side) land portions 53 provided on the lower surface 51b. However, as the circuit board 51 is miniaturized, both of them approach each other. It becomes a state.

  Therefore, the circuit board 51 of the conventional surface mount electronic circuit unit is placed on a mother board (not shown) of an electronic device (not shown), and the land portion 53 is a conductive pattern (not shown) on the mother board. ), The solder 57 and the conductor 54 and the land portion 53 are brought into conduction with each other due to the soldering.

JP 2001-284756 A

  In the conventional surface mount type electronic circuit unit, the lower end of the solder 57 for attaching the mounting leg 56a and the conductor 54 is exposed from the lower surface 51b of the circuit board 51. Therefore, as the circuit board 51 is downsized, Therefore, when the circuit board 51 is surface-mounted on the mother board, the solder 57, the conductor 54, and the land part 53 are in a state of being close to each other. There is a problem in that a situation where electrical connection is caused by solder during mounting occurs.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a surface mounting type electronic circuit unit that is free from defects caused by soldering during surface mounting and has high surface mounting reliability.

  As a first means for solving the above problems, a circuit pattern having a wiring pattern provided on the upper surface and a land portion provided on the lower surface, an electronic component mounted on the wiring pattern, and a vertical direction A penetrating portion provided on the circuit board, a conductor provided on a wall surface of the penetrating portion, and a box-shaped cover attached to the circuit board in a state of covering the electronic component. The mounting legs provided on the cover are soldered and attached to the conductor in a state of being located in the through portion, and an insulating film is positioned on the lower surface of the solder and in the vicinity of the lower surface of the solder. It was set as the structure provided ranging over the lower surface of the said circuit board.

As a second solution, the insulating film is formed of a solder resist film.
Further, as a third solution, the penetrating portion is provided in a vertically extending notch portion provided at a position of the end surface of the circuit board or / and a position away from the end surface of the circuit board. It was set as the structure formed with the through-hole penetrated in the up-down direction.

The surface mount electronic circuit unit of the present invention includes a circuit board having a wiring pattern provided on the upper surface and a land portion provided on the lower surface, an electronic component mounted on the wiring pattern, and vertically penetrating. A through-hole provided in the circuit board, a conductor provided on the wall surface of the through-hole, and a box-shaped cover attached to the circuit board in a state of covering the electronic component are provided in the cover. The mounting legs are soldered and attached to the conductor in a state where they are located in the through portion, and the insulating film is provided across the lower surface of the solder and the lower surface of the circuit board located near the lower surface of the solder. It was.
Thus, when the insulating film is provided across the lower surface of the solder and the lower surface of the circuit board located in the vicinity of the lower surface of the solder, the insulating film is blocked between the solder and the land portion in the close state. When the board is surface-mounted on the mother board, there is no conduction between the solder and the land due to the solder at the time of surface mounting, and soldering defects at the time of surface mounting can be eliminated. In addition, it is possible to provide a surface mount electronic circuit unit with high surface mount reliability.

  Further, since the insulating film is formed of a solder resist film, the structure is simple and an inexpensive one can be obtained.

  Further, the through portion is formed by a notch portion penetrating in the vertical direction provided at the position of the end face of the circuit board or / and a through hole penetrating in the vertical direction provided at a position away from the end face of the circuit board. Therefore, the structure is simple, and an insulating film can be formed in the state of a large plate substrate, and a product with good productivity can be obtained.

  FIG. 1 is a plan view of a surface mount electronic circuit unit according to a first embodiment of the present invention. FIG. 2 is a plan view of the surface mount electronic circuit unit according to the present invention. FIG. 3 is a bottom view according to the first embodiment, and FIG. 3 is a cross-sectional view of an essential part according to the first embodiment of the surface mount electronic circuit unit of the present invention.

  4 is a plan view showing a first step for explaining the manufacturing method according to the first embodiment of the surface mount electronic circuit unit of the present invention, and FIG. 5 is a surface mount electronic circuit unit of the present invention. FIG. 6 is a plan view showing a second step for explaining the manufacturing method according to the first embodiment of the present invention, and FIG. 6 shows the manufacturing method according to the first embodiment of the surface mount electronic circuit unit of the present invention. It is a bottom view which shows the 2nd process for this.

  7 is a bottom view showing a third step for explaining the manufacturing method according to the first embodiment of the surface mount electronic circuit unit of the present invention, and FIG. 8 is a surface mount electronic circuit unit of the present invention. FIG. 9 is a cross-sectional view of a main part according to a second embodiment of the surface mount electronic circuit unit of the present invention.

  Next, the configuration of the surface mount electronic circuit unit according to the present invention will be described with reference to FIGS. 1 to 3. One or more circuit boards 1 made of insulating resin, low-temperature fired ceramic, or the like are laminated. An upper surface 1a, a lower surface 1b, and an end surface 1c positioned on the outer peripheral portion, and a through portion 1d that is provided at a position of the end surface 1c and includes a notch that penetrates in the vertical direction.

  A wiring pattern 2 is formed on the upper surface 1a of the circuit board 1, and a plurality of land portions 3 for signals (hot side) are provided on the lower surface 1b of the circuit board 1, and a through-hole 1d is formed. A conductor 4 is provided on the wall surface, and various electronic components 5 are mounted on the wiring pattern 2 to form a desired electric circuit.

  The metal box-shaped cover 6 includes a box-shaped cover portion 6a and a mounting leg 6b extending downward from the cover portion 6a. The cover 6 covers the electronic component 5 with the cover portion 6a, and the mounting leg. Solder 7 is attached to the conductor 4 in a state where 6b is inserted into the through portion 1d.

  The insulating film 8 is formed of an insulating material such as a solder resist film, and is provided across the lower surface of the solder 7 and the lower surface 1 b of the circuit board 1 located in the vicinity of the lower surface of the solder 7. The insulating film 8 is in a state of being covered, and the insulating film 8 blocks the solder 7 and the land portion 3 that are in close proximity to each other.

  As shown in the first embodiment (particularly, see FIG. 3), when the lower end of the conductor 4 is exposed on the lower surface 1b of the circuit board 1, the lower end of the conductor 4 is covered with the insulating film 8. Of course, there is a conductor 4 whose lower end is in the middle of the wall surface of the penetrating portion 1d. In this case, the solder 7 flows down to the lower surface 1b, and the lower surface of the solder 7 is insulated. The film is covered with the film 8.

  In addition, a solder resist film (not shown) is provided on the lower surface 1b of the circuit board 1 with the land portions 3 exposed, and in this state, the mounting legs 6b and the conductors 4 are soldered 7. Thereafter, the insulating film 8 is formed, or the mounting legs 6b and the conductor 4 are soldered 7, and then a solder resist film is formed on the entire lower surface 1b except for the land portion 3, and the insulating film 8 is formed. You may make it form simultaneously.

  With this configuration, the surface mount electronic circuit unit of the present invention is formed. The surface mount electronic circuit unit of the present invention is not shown here, but the circuit board 1 is a mother board (not shown) of an electronic device (not shown). The land portion 3 is soldered to a conductive pattern (not shown) provided on the mother board and surface-mounted.

  As the circuit board 1 is further reduced in size, the solder 7 and the signal (hot side) land 3 are closer to each other, but the lower surface of the solder 7 is covered with the insulating film 8. Therefore, when the circuit board 1 is surface-mounted on the mother board, the solder 7 and the land portion 3 are not electrically connected by the solder at the time of surface mounting, and the soldering failure at the time of surface mounting can be eliminated. As a result, reliable soldering and high surface mounting reliability can be obtained.

  Next, the manufacturing method of the first embodiment of the surface mount electronic circuit unit according to the present invention will be described with reference to FIGS. 4 to 7. First, in the first step shown in FIG. A large plate substrate 11 is prepared.

  And although not shown here, the wiring pattern 2 and the land part 3 are provided in the location corresponding to each circuit board (part surrounded by a two-dot chain line) 1 of the large-size substrate 11 and adjacent to each other. Between the circuit boards 1, a through hole 12 serving as a through portion 1 d made of a notch is provided, and a conductor 4 is formed on the wall surface of the through hole 12.

  Next, in the second step shown in FIGS. 5 and 6, cream solder is applied on the circuit board 1 and in the through holes 12. First, the electronic component 5 is placed on the cream solder, and then the electronic component 5 is mounted. When the mounting leg 6b is inserted into the through-hole 12 while being covered with the cover 6a of the cover 6, and then transported into the reflow furnace to melt the cream solder, the solder of the electronic component 5 to the wiring pattern 2 is soldered. At the same time, the attachment leg 6b to the conductor 4 is soldered.

  Note that the soldering of the electronic component 5 and the soldering 7 of the cover 6 may be performed by separate processes.

  Next, in the third step shown in FIG. 7, the insulating film 8 is provided across the lower surface of the solder 7 located on the lower surface of the through hole 12 and the lower surface 1 b of the circuit board 1 located in the vicinity of the lower surface of the solder 7. Then, the lower surface of the solder 7 is covered with the insulating film 8.

  As described above, the insulating film 8 is formed in advance by providing a solder resist film (not shown) on the lower surface 1b of the circuit board 1, and in this state, the solder 7 of the mounting leg 6b and the conductor 4 is formed. After the attachment, the insulating film 8 is formed, or after the mounting legs 6b and the conductor 4 are soldered 7, a solder resist film is formed on the entire lower surface 1b except for the land portion 3, The insulating film 8 may be formed at the same time.

  And in the last process, when it cut | disconnects in the position shown with a dashed-two dotted line, while being formed in each surface mount type electronic circuit unit as shown in FIGS. 1-3, it cut | disconnects in the position of the through-hole 12. FIG. Thus, the circuit board 1 is formed with a through-hole 1d made of a notch.

  8 and 9 show a second embodiment of the surface mount electronic circuit unit according to the present invention. In the second embodiment, the penetrating portion 1d is provided at a position away from the end face 1c of the circuit board 1. FIG. A mounting leg 6b formed by a through hole penetrating in the vertical direction and inserted into the through hole as the through portion 1d is soldered to the conductor 4, and an insulating film 8 is formed on the solder 7 in the through portion 1d. It is provided across the lower surface and the lower surface 1 b of the circuit board 1 located in the vicinity of the lower surface of the solder 7.

  Since other configurations are the same as those in the first embodiment, the same parts are denoted by the same reference numerals, and the description thereof is omitted here.

The top view which concerns on 1st Example of the surface mount-type electronic circuit unit of this invention. 1 is a bottom view according to a first embodiment of a surface mount electronic circuit unit of the present invention. FIG. The principal part sectional view concerning the 1st example of the surface mounting type electronic circuit unit of the present invention. The top view which concerns on 1st Example of the surface mounted electronic circuit unit of this invention, and shows the 1st process for demonstrating the manufacturing method. The top view which concerns on 1st Example of the surface mount-type electronic circuit unit of this invention, and shows the 2nd process for demonstrating the manufacturing method. The bottom view which shows the 2nd process for demonstrating the manufacturing method concerning the 1st Example of the surface mount-type electronic circuit unit of this invention. The bottom view which concerns on 1st Example of the surface mount-type electronic circuit unit of this invention, and shows the 3rd process for demonstrating the manufacturing method. The bottom view which concerns on 2nd Example of the surface mount-type electronic circuit unit of this invention. Sectional drawing of the principal part which concerns on 2nd Example of the surface mount-type electronic circuit unit of this invention. The perspective view of the conventional surface mount-type electronic circuit unit. The bottom view of the conventional surface mount-type electronic circuit unit. Sectional drawing of the principal part of the conventional surface mount-type electronic circuit unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1: Circuit board 1a: Upper surface 1b: Lower surface 1c: End surface 1d: Through part 2: Wiring pattern 3: Land part 4: Conductor 5: Electronic component 6: Cover 6a: Cover part 6b: Mounting leg 7: Solder 8: Insulation Film 11: Large plate substrate 12: Through hole

Claims (3)

A circuit board having a wiring pattern provided on the upper surface and a land portion provided on the lower surface; an electronic component mounted on the wiring pattern; and a through part provided in the circuit board penetrating in the vertical direction; The conductor provided on the wall surface of the penetrating portion and the box-shaped cover attached to the circuit board in a state of covering the electronic component, and the mounting leg provided on the cover includes the penetrating In the state where it is located in the part, it is attached by soldering to the conductor, and the insulating film is provided across the lower surface of the solder and the lower surface of the circuit board located in the vicinity of the lower surface of the solder. A featured surface mount electronic circuit unit. 2. The surface mount electronic circuit unit according to claim 1, wherein the insulating film is formed of a solder resist film. The penetrating part is a notch part penetrating in the vertical direction provided at the position of the end face of the circuit board, and / or a through hole penetrating in the vertical direction provided at a position away from the end face of the circuit board. 3. The surface mount electronic circuit unit according to claim 1, wherein the surface mount electronic circuit unit is formed.

Images